In a mobile water treatment system, water treatment equipment is provided in a portable vehicle, such as a truck, trailer, skid or transport container, and delivered to a location where water treatment is required. Such mobile water treatment systems are used when it would be less economical to build a permanent treatment plant. For example, temporary water treatment may be required when a power plant is commissioned; when permanent water treatment plants are being repaired; for forestry or mining camps; or, to provide feed water for boilers that operate seasonally. In general, treated water may be required at a particular site for a period of time that may be up to several years but is still less that the lifetime of a permanent water treatment plant. Alternatively, treated water may be required permanently but for only part of each year, for example between about 1,000 to 2,000 hours per year. In both of these cases, it can be less expensive for the site operator to rent a mobile water treatment system than to build a permanent facility.
The vehicle in a mobile water treatment system may be fitted with, among other things, various sorts of tanks, media, pumps, pipes, controls and instrumentation. In the MobileFlow™ system by GE Water & Process Technologies, for example, a transport truck trailer is fitted with six tanks that are made of steel, lined with rubber, and capable of being pressurized to 100 psi. The tanks are connected together with a standard piping system that allows the tanks to be connected together in series or parallel. Each tank can be filled with one of a selection of available media types such as granular filter media, deoxygenation media, or ion exchange resin beads. For example, to provide demineralization treatment some tanks are filled with cation exchange resin, other tanks are filled with strong base anion exchange resin, and another tank is filled with a mixed bed. Each trailer also includes an instrumentation package, a controls package and a heating system. The trailer is set up and tested at a service centre, and then trucked to the treatment site to be put in operation.
In cases where resin beds are used, the resin beads must be regenerated from time to time. In the MobileFlow™ system, the vehicle is returned to the service centre where the resin beads are transferred into regeneration vessels and stored there until the beads can be regenerated. Previously regenerated resin is transferred back on to the vehicle, which can then be sent back to the same or another water treatment site. In this way, water for regeneration is not required at the treatment site, which may be in a water scarce location, and regeneration waste water does not need to be discharged at the water treatment site, which may not have a waste water discharge permit. Further, comprehensive regeneration processes, including for example backwashing and air scrubbing, treatment with regenerants, rinsing with deionized water and quality testing, can be provided at the service centre.